<!DOCTYPE html>
<html lang="zh-CN">

<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <style>
    .red-point {
      position: relative;
    }

    .red-point::before {
      content: " ";
      border: 3px solid red;
      /*设置红色*/
      border-radius: 3px;
      /*设置圆角*/
      position: absolute;
      z-index: 1000;
      right: 0;
      margin-right: -8px;
    }
  </style>
</head>

<body>
  <span class="red-point">设置</span>
</body>

</html>